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From: Stefan Metzmacher <metze@samba.org>
To: Jeremy Allison <jra@samba.org>, Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Jens Axboe <axboe@kernel.dk>,
	Linux API Mailing List <linux-api@vger.kernel.org>,
	Dave Chinner <david@fromorbit.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Samba Technical <samba-technical@lists.samba.org>,
	io-uring <io-uring@vger.kernel.org>
Subject: Re: copy on write for splice() from file to pipe?
Date: Fri, 10 Feb 2023 20:29:57 +0100	[thread overview]
Message-ID: <c3f166d3-35b6-25cf-6ccb-8650e90a5a17@samba.org> (raw)
In-Reply-To: <Y+aKuC1PuvX4STEI@jeremy-acer>

Am 10.02.23 um 19:19 schrieb Jeremy Allison:
> On Fri, Feb 10, 2023 at 09:57:20AM -0800, Andy Lutomirski via samba-technical wrote:
>>
>> (And if Samba needs to make sure that future writes don't change the
>> outgoing data even two seconds later when the data has been sent but
>> not acked, then maybe a fancy API could be added to help, or maybe
>> Samba shouldn't be using zero copy IO in the first place!)
> 
> Samba doesn't need any of this. The simplest thing to do is
> to restrict splice-based zero-copy IO to files leased by
> a single client, where exclusive access to changes is controled
> by the client redirector.

Yes, I guess we can use it if the file is read-only (from it's acls),
or when the client has a read lease. And of course we can have an I don't care
option, maybe reusing 'use sendfile = yes' as that has the same problem in
the existing code already.

metze

  reply	other threads:[~2023-02-10 19:30 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-09 13:55 copy on write for splice() from file to pipe? Stefan Metzmacher
2023-02-09 14:11 ` Matthew Wilcox
2023-02-09 14:29   ` Stefan Metzmacher
2023-02-09 16:41 ` Linus Torvalds
2023-02-09 19:17   ` Stefan Metzmacher
2023-02-09 19:36     ` Linus Torvalds
2023-02-09 19:48       ` Linus Torvalds
2023-02-09 20:33         ` Jeremy Allison
2023-02-10 20:45         ` Stefan Metzmacher
2023-02-10 20:51           ` Linus Torvalds
2023-02-10  2:16   ` Dave Chinner
2023-02-10  4:06     ` Dave Chinner
2023-02-10  4:44       ` Matthew Wilcox
2023-02-10  6:57         ` Dave Chinner
2023-02-10 15:14           ` Andy Lutomirski
2023-02-10 16:33             ` Linus Torvalds
2023-02-10 17:57               ` Andy Lutomirski
2023-02-10 18:19                 ` Jeremy Allison
2023-02-10 19:29                   ` Stefan Metzmacher [this message]
2023-02-10 18:37                 ` Linus Torvalds
2023-02-10 19:01                   ` Andy Lutomirski
2023-02-10 19:18                     ` Linus Torvalds
2023-02-10 19:27                       ` Jeremy Allison
2023-02-10 19:42                         ` Stefan Metzmacher
2023-02-10 19:42                         ` Linus Torvalds
2023-02-10 19:54                           ` Stefan Metzmacher
2023-02-10 19:29                       ` Linus Torvalds
2023-02-13  9:07                         ` Herbert Xu
2023-02-10 19:55                       ` Andy Lutomirski
2023-02-10 20:27                         ` Linus Torvalds
2023-02-10 20:32                           ` Jens Axboe
2023-02-10 20:36                             ` Linus Torvalds
2023-02-10 20:39                               ` Jens Axboe
2023-02-10 20:44                                 ` Linus Torvalds
2023-02-10 20:50                                   ` Jens Axboe
2023-02-10 21:14                                     ` Andy Lutomirski
2023-02-10 21:27                                       ` Jens Axboe
2023-02-10 21:51                                         ` Jens Axboe
2023-02-10 22:08                                           ` Linus Torvalds
2023-02-10 22:16                                             ` Jens Axboe
2023-02-10 22:17                                             ` Linus Torvalds
2023-02-10 22:25                                               ` Jens Axboe
2023-02-10 22:35                                                 ` Linus Torvalds
2023-02-10 22:51                                                   ` Jens Axboe
2023-02-11  3:18                                             ` Ming Lei
2023-02-11  6:17                                               ` Ming Lei
2023-02-11 14:13                                               ` Jens Axboe
2023-02-11 15:05                                                 ` Ming Lei
2023-02-11 15:33                                                   ` Jens Axboe
2023-02-11 18:57                                                     ` Linus Torvalds
2023-02-12  2:46                                                       ` Jens Axboe
2023-02-10  4:47       ` Linus Torvalds
2023-02-10  6:19         ` Dave Chinner
2023-02-10 17:23           ` Linus Torvalds
2023-02-10 17:47             ` Linus Torvalds
2023-02-13  9:28               ` Herbert Xu
2023-02-10 22:41             ` David Laight
2023-02-10 22:51               ` Jens Axboe
2023-02-13  9:30               ` Herbert Xu
2023-02-13  9:25           ` Herbert Xu
2023-02-13 18:01             ` Andy Lutomirski
2023-02-14  1:22               ` Herbert Xu
2023-02-17 23:13                 ` Andy Lutomirski
2023-02-20  4:54                   ` Herbert Xu

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